ACT Math

Combinations

order does not matter

MATH PRB 3(_n^Cr)

(n!)/((n-r)!r!)

Permutations

Order matters

n!/(n-r)!

r blanks and number of options in each blank

Combinations

order does not matter

MATH PRB 3(_n^Cr)

(n!)/((n-r)!r!)

Permutations

Order matters

n!/(n-r)!

r blanks and number of options in each blank

|x-midpoint| < variance

abs inequality

reflected across x axis

negate y

log_b(M*N) =

log_b(M) + log_b(N)

log_b(M/N) =

log_b(M) - log_b(N)

log_b(M^c)

Clog_b(M)

Area of rhombus, square, kite

(d₁d₂)/2

trapezoid area

(b₁+b_{2)/2 *h}

linear ratio

a : b

area ratio

a² : b²

volume ratio

a³ : b³

elipse equation

(x-h)²/a² + (y-k)²/b² = 1

a is horizontal

b is vertical

2a or 2b are lengths of axis

center of circle to chord

bisects chord

triangle with diameter and 2 chords

right triangle

csc x

h/o

1/sinx

sec x

h/a

1/cos x

cot x

a/o

1/tan x

Law of sines

sinA/a = sin B/b = sinC/c

2 angles 2 sidesL

Law of cosines

c² = a² + b² - 2abcos C

1 angle 3 sides

tan x

sin x / cos x

sin x

cos(90-x)

sin²x + cos²x =

1

probability or

add probabilitiespro

probability and

multiply probabilities

45 45 90 triangle sides

xsqrt2

x

x

30 60 90 triangle sides

2x

xsqrt3

x

volume of cylindar

V = π r ² h

sum of angles in polygon

( n – 2)180°

surface area of sphere

S = 4π r ²

distance formula